Ultra-broadband and high-efficiency hierarchical metasurface solar absorber designed by a dual-population co-evolution genetic algorithm

Abstract

As a core clean energy source to address energy crisis and advance carbon neutrality, the efficient utilization of solar energy hinges on broadband light absorption, which is pivotal for overcoming the bottlenecks in energy conversion. To overcome the design limitations of traditional solar absorbers regarding high-efficiency broadband absorption and robustness in complex environments, this study proposes an improved genetic algorithm, namely, DCD-GA, based on a dual-population co-evolution mechanism and a dynamic hierarchical roulette strategy. Based on this method, a TiN/TiO₂/Ti hierarchical metasurface solar absorber is designed. This structure employs a multi-layered cascaded metal–insulator–metal (MIM) architecture, achieving an average absorption efficiency of 96.27% in the 300–3000 nm wavelength range. Under AM1.5 solar spectrum conditions, the total absorption accounts for 96.82% of the total solar spectral energy, and at the wavelengths of 2633 nm and 2403 nm, absorption efficiencies exceeding 90% and 94% are achieved, respectively. Meanwhile, the thermal radiation efficiency of this structure remains at 95.57–97.34% in the temperature range of 200–2000 K, exhibiting a stable high-temperature performance. In addition, benefiting from the centrosymmetric micro–nano array design, the absorber exhibits polarization insensitivity, maintaining high absorption efficiency over an incident angle range of 0°–60° for both TE and TM modes. These characteristics indicate that this absorber has promising application prospects in fields such as solar thermophotovoltaics, high-temperature photocatalysis, infrared light sources, and solar thermal management systems.